Bicycle MechanicsBroken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

I have a road frame I'd like to use for a fixed gear conversion, just my size. I was trying to swap out the old fixed cup cottered crank bottom bracket with a cartridge one (a cheap Shimano UN-53) when I stripped the threads. Now I really do want to use this frame, and right now, buying a brand new frame or even taking it to the shop to get retapped seems a little on the expensive side right now.

I was thinking of a quick fix that would work like so: file off the threads on the bottom bracket and just JB weld it on. It seems like it'll work, but is there anything I'm overlooking? (the other side of the bb threads on fine). Clearly I'm not going to be doing anything to the bb after this, but I figure by the time I need to I'd be on to bigger and better things (track frame, et al). Anyhow, I'm really frustrated with this. Help!

I can't recall who makes it...but there is a Taiwanese company that makes a B.B. that tightens together instead of into the threads. Kind of like Mavic's old B.B. Lots of folks have used these with no problem.

I can't recall who makes it...but there is a Taiwanese company that makes a B.B. that tightens together instead of into the threads. Kind of like Mavic's old B.B. Lots of folks have used these with no problem.

Hmm, at least two of my bikes have such BBs. They have a smooth body with threads only on one side, and a sort of thin ring that screws onto these threads and is completely smooth on the other side. The body and ring "compress" the BB shell and everything holds just fine without threads in the BB shell. The only catch is that I needed two splined tools to tighten the ring.

They mustn't be hard to find, as my LBS didn't seem to have any trouble finding them, even in the odd sizes I asked.